Go Back   ChinaRiders Forums > Technical/Performance > ATVs
Register FAQ Community Calendar Today's Posts Search
Reply
 
Thread Tools Search this Thread Display Modes
Old 03-20-2023, 10:13 PM   #1
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Tao Tao 125 starting issues

Pulled out my son's atv to get it started up and him riding again and immediately ran into an issue. Battery was dead, charged battery and engine struggles to spin over still. Battery dies very quickly. Battery is of unknown age so got a new battery. Engine still sounds like it's struggling to spin over when pressing the starter button and new battery dies pretty quickly. Pulled spark plug to check spark and noticed it's dry and black, almost sooty. Without plug in place engine spins freely. pulled Carb and disassembled and cleaned everything, reassembled and installed. went to start and get a click from starter solenoid, but nothing from the starter. removed the starter and found it was burned up, brush holder melted, one of the brushes floating. Ordered starter.

When new starter came I was able to get the engine running, for about 10 seconds. let off throttle and engine stalled, couldn't get it started again. Here's where I'm at now. I replaced the carb, had one that I bought last year and it's never been run. still nothing. When trying to start engine, if I give it any throttle at all it will not turn over, stops turning over as soon as I crack the throttle. If the idle speed screw is turned in too far, same thing. When it is spinning over it 'catches' for lack of a better word and stops spinning. I adjusted valves today, .006mm, no improvement. I have a new starter solenoid, haven't installed it. The CDI box was replaced last summer. I had a new coil and plug wire so installed that today as well.

Where do I go from here? I've done everything I know to do and it just will not run.


 
Reply With Quote
Old 03-21-2023, 02:29 PM   #2
clash 168cc   clash 168cc is offline
 
Join Date: Jul 2022
Posts: 94
Fresh non-eth gas. Water/sludge may be in fuel. New spark plug.


 
Reply With Quote
Old 03-21-2023, 04:53 PM   #3
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by clash 168cc View Post
Fresh non-eth gas. Water/sludge may be in fuel. New spark plug.
It has fresh gas in it, spark plug is a new ngk


 
Reply With Quote
Old 03-21-2023, 04:55 PM   #4
JerryHawk250   JerryHawk250 is offline
Moderator
 
JerryHawk250's Avatar
 
Join Date: Oct 2016
Location: Houma, La.
Posts: 11,713
Check for crack intake or leaks in vacuum lines.
__________________
2024 Linhai 300 ATV 4x4
2023 Lifan Lycan 250 Chopper
2023 Venom Evader
2022 Lifan KPX250
2020 Kawasaki Vulcan S (Sold)
2004 Honda ST 1300
2016 Black Hawk 250 (sold)
Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster
2016 Cazador180 XL
2014 Coolster150
JerryHawk250.com
My YouTube Channel


 
Reply With Quote
Old 03-21-2023, 07:41 PM   #5
krat   krat is offline
 
Join Date: Nov 2019
Location: KY
Posts: 277
If it ran when you parked it for the winter it is a storage based issue.

Air-fuel-spark!

Check for all of them rather than just grinding away until the battery fries everything.

Putting fresh gas in the tank does not mean it is getting to the cylinder and a new battery does not guarantee you are getting spark.

Add to that the sluggish turnover sounds like you are starving for air.

After winter storage you might have a rat's nest in the air box, shellac inside the carb or a clogged fuel line.

Speaking of rats, they love the soy based insulation on chinabike wires.

You still have a number of simple things to check.
__________________
%90 of the Chinese motorbikes ever made are still on the road. The other %10 made it back home.


 
Reply With Quote
Old 03-21-2023, 08:00 PM   #6
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by krat View Post
If it ran when you parked it for the winter it is a storage based issue.

Air-fuel-spark!

Check for all of them rather than just grinding away until the battery fries everything.

Putting fresh gas in the tank does not mean it is getting to the cylinder and a new battery does not guarantee you are getting spark.

Add to that the sluggish turnover sounds like you are starving for air.

After winter storage you might have a rat's nest in the air box, shellac inside the carb or a clogged fuel line.

Speaking of rats, they love the soy based insulation on chinabike wires.

You still have a number of simple things to check.
I’ve checked spark, it’s there. Even with no air box at all, same thing. Fuel line was replaced, as was shut off valve. Fuel barely trickled out which led to the lines being replaced. New fuel filter installed at same time.

As far as I can tell the basic stuff has been checked. The struggling to turn over was an issue last year too, that’s not new but it would still start pretty easily. Now not at all.


 
Reply With Quote
Old 03-21-2023, 09:15 PM   #7
clash 168cc   clash 168cc is offline
 
Join Date: Jul 2022
Posts: 94
Can rarely be sheared flywheel key throwing off timing. Recheck valve gap is right with piston at top and check compression. Spray starting fluid. Shutting off while revving is no fuel or choke not closed (cold engine needs choke). Use your hand over carb to choke engine and also try while revving after it starts.


 
Reply With Quote
Old 03-21-2023, 10:20 PM   #8
dirtbkr188   dirtbkr188 is offline
 
dirtbkr188's Avatar
 
Join Date: Aug 2009
Posts: 572
Unless it is a typo in your first post, if you set the valves at .006mm, you have no valve clearance at all. The recommended settings for these engines is .002" (0.05mm) for intake and .003" (0.08mm) for the exhaust.




 
Reply With Quote
Old 03-22-2023, 06:17 AM   #9
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by dirtbkr188 View Post
Unless it is a typo in your first post, if you set the valves at .006mm, you have no valve clearance at all. The recommended settings for these engines is .002" (0.05mm) for intake and .003" (0.08mm) for the exhaust.


You are correct. Typo on my part. Valves were adjusted with a piece of shim stock that measured at .003”.


 
Reply With Quote
Old 03-22-2023, 04:34 PM   #10
david3921   david3921 is offline
 
Join Date: Feb 2009
Location: Michigan
Posts: 1,043
Quote:
Originally Posted by CorvZ061 View Post
You are correct. Typo on my part. Valves were adjusted with a piece of shim stock that measured at .003”.
Make sure that the valves were set on the correct stroke of the engine. Best way to check is that the arms are loose once it's set to TDC.

Also, this statement from above is pretty strange;
"When trying to start engine, if I give it any throttle at all it will not turn over, stops turning over as soon as I crack the throttle. If the idle speed screw is turned in too far, same thing."

Turning the throttle or adjusting the carb shouldn't have anything to do with cranking the motor.

Member that that these quads need the brake activated to start. I've had a rear brake wire that broke which kept the quad from starting but it turned over.
__________________
2012 Kawasaki Versys
1984 Honda Magna V65
2016 Rhino 250
2016 Tao Tao 125D


 
Reply With Quote
Old 03-22-2023, 05:06 PM   #11
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by david3921 View Post
Make sure that the valves were set on the correct stroke of the engine. Best way to check is that the arms are loose once it's set to TDC.

Also, this statement from above is pretty strange;
"When trying to start engine, if I give it any throttle at all it will not turn over, stops turning over as soon as I crack the throttle. If the idle speed screw is turned in too far, same thing."

Turning the throttle or adjusting the carb shouldn't have anything to do with cranking the motor.

Member that that these quads need the brake activated to start. I've had a rear brake wire that broke which kept the quad from starting but it turned over.
I will record it. It’s very strange. But it seems if it’s getting too much air it won’t spin over.


 
Reply With Quote
Old 03-22-2023, 06:00 PM   #12
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by david3921 View Post
Make sure that the valves were set on the correct stroke of the engine. Best way to check is that the arms are loose once it's set to TDC.

Also, this statement from above is pretty strange;
"When trying to start engine, if I give it any throttle at all it will not turn over, stops turning over as soon as I crack the throttle. If the idle speed screw is turned in too far, same thing."

Turning the throttle or adjusting the carb shouldn't have anything to do with cranking the motor.

Member that that these quads need the brake activated to start. I've had a rear brake wire that broke which kept the quad from starting but it turned over.
Here’s the video. As you can see it tried to start initially, but never does more than that. But also depress the throttle and it quits. Also does the same if the idle speed screw is turned in anymore. No idea where idle screw needs to be at right now, ut hasn’t run at all to be able to adjust anything.




Last edited by CorvZ061; 03-22-2023 at 06:01 PM. Reason: Added link to video
 
Reply With Quote
Old 03-22-2023, 06:38 PM   #13
david3921   david3921 is offline
 
Join Date: Feb 2009
Location: Michigan
Posts: 1,043
Never seen that before. Pretty weird. I think I would start there in the investigation. The throttle and front brakes are an assembly. Maybe by pushing the thumb throttle it's breaking the brake connection. Also, I see that it has a lanyard. Mine didn't come with one. Mine came with the rear one and the switch. There could be a possibility of corrosion in contacts of these safety features. I'm also curious about the small box on top. What's that for?
__________________
2012 Kawasaki Versys
1984 Honda Magna V65
2016 Rhino 250
2016 Tao Tao 125D


 
Reply With Quote
Old 03-22-2023, 06:46 PM   #14
CorvZ061   CorvZ061 is offline
 
Join Date: Mar 2023
Posts: 16
Quote:
Originally Posted by david3921 View Post
Never seen that before. Pretty weird. I think I would start there in the investigation. The throttle and front brakes are an assembly. Maybe by pushing the thumb throttle it's breaking the brake connection. Also, I see that it has a lanyard. Mine didn't come with one. Mine came with the rear one and the switch. There could be a possibility of corrosion in contacts of these safety features. I'm also curious about the small box on top. What's that for?
If we’re looking at the same box that’s the gear indicator. I don’t think it’s a safety cut out issue, I could be wrong on that. Reason I don’t think it’s a safety cut out is that it does the same with idle screw. If I turn it in even 1/2 turn further it sounds like it’s struggling to turn over. This is the main issue I’d like to fix, because if I can give it throttle while turning over I feel like I’d be able to get it to run when it ‘tries’ to start.

The lanyard switch seems to work? I’ll bypass it just to be sure.

I also jumped the starter solenoid today to make sure it’s not something dumb like a bad solenoid.


 
Reply With Quote
Old 03-22-2023, 08:44 PM   #15
shad88   shad88 is offline
 
Join Date: Mar 2021
Location: Boston
Posts: 21
Sounds like it may be the one way clutch on the flywheel not allowing the engine to crank over properly.


 
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:56 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.